Simvastatin Reduces Fibrosis and Protects Against Muscle Weakness after Massive Rotator Cuff Tear

Patients with chronic rotator cuff tears often suffer from muscle fiber atrophy, a decrease in strength, fibrosis and fat accumulation throughout the muscle, commonly referred to as fatty degeneration (1). The lipid that accumulates in torn rotator cuff muscles is an appealing therapeutic target for preventing inflammation and atrophy, as large lipid droplets often serve as sites of production for proinflammatory signaling molecules and cytokines. Lipid lowering medications, such as statins (HMG CoA reductase inhibitors), are commonly prescribed to patients with hypercholesterolemia or cardiovascular disorders. There is a positive correlation between hypercholesterolemia and developing a rotator cuff tear (3), but it is unknown whether statin medication could be used to decrease fatty degeneration after rotator cuff tear. We hypothesized that administering a statin medication, simvastatin, would protect torn rotator cuff muscles from developing fatty degeneration. To test this hypothesis we treated rats that underwent a full-thickness supraspinatus tear with simvastatin or vehicle for four weeks, and then removed the muscles to evaluate fat accumulation, inflammation, strength and regeneration.